On the surface of epidermis, a thin sebaceous film is formed. Such film has actions for preventing foreign matters in the environment from entering into the epidermis, for protecting the skin from irritation of various substances, or minimizing moisture loss for humectating the skin surface. On the other hand, an excess sebum causes an oily feeling in touch, greasy and shiny skin and worsening in makeup, and also causes seborrheic dermatitis such as acne.
Therefore, several methods such as those for physiologically suppressing the sebaceous secretion using pharmacologically active substances and physically absorbing an excessively secreted sebum with an oil-adsorbing substance have been examined. However, any useful pharmacologically active substance effective for sebum suppression has not been discovered, and is not in practical use.
A method for removing an excess sebum in the latter using a grease-absorbing paper is known, but this method is not satisfactory in a sebum-absorbing ability, though acceptable as a first-aid treatment. Further, for example, a pack containing lipophilic titanium dioxide or lipophilic silicon dioxide (JP-A-57-112314); a cosmetic containing healstone (Bakuhanseki) powder with a median particle diameter of 5-15 μm (JP-A-09-263528); and a cosmetic sheet containing porous granules (microcapsules) encapsulating a functional treating agent attached onto the surface or inside of a sheet material (JP-A-02-36114) have been proposed, but these are not satisfactory for practical use and in sebum-absorbing ability, and further are deficient in an actual feeling of the removal of the sebum as compared with the grease-absorbing paper. In order to improve an actual feeling of sebum-free, for example, in the grease-absorbing paper, a method is known in which a pattern on the paper disappears or becomes clear when sebum is absorbed (JP-A-10-298030), but the method can not be broadly applied for various types of cosmetics.
In JP-A-2001-72566, a sheet-like pack cosmetic comprising an oil-absorbing powder, which absorbs a specific amount of squalane, is described. This pack cosmetic is superior in sebum-absorbing ability as well as in improving and preventing worsening in makeup; however, in order to supplement effects such as moistness, tightness and tension, additional cosmetics such as lotion and cream have to be used.
An object of the present invention is to provide a cosmetic which can adequately absorb sebum and thus exhibit a superior effect of improving or preventing oiliness of the skin and worsening in makeup, is easy to use, imparts an actual feeling of the removal of the sebum to users, as well as effectively provides a substance having an ability to improve the skin qualities such as moistness, tightness and tension to the skin.